The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 60, we have over 367,000 sequences, and we’ve crossed 11,000 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A339571 A133058 with duplicates removed. 0
 1, 4, 8, 2, 12, 3, 24, 16, 21, 7, 27, 48, 32, 30, 15, 5, 34, 64, 36, 18, 54, 41, 80, 120, 45, 59, 104, 150, 75, 123, 91, 142, 194, 97, 151, 206, 262, 131, 189, 248, 308, 77, 139, 202, 266, 133, 199, 334, 167, 237, 380, 95, 169, 244, 320, 158, 79, 82, 164, 86 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..60. Dana G. Korssjoen, Biyao Li, Stefan Steinerberger, Raghavendra Tripathi, and Ruimin Zhang, Finding structure in sequences of real numbers via graph theory: a problem list, arXiv:2012.04625 [math.CO], Dec 08, 2020. See Section 2.6. MATHEMATICA DeleteDuplicates@ Block[{a = {1, 1}, k = 1}, Do[AppendTo[a, If[# == 1, a[[-1]] + i + 1, a[[-1]]/#]] &@ GCD[a[[-1]], i], {i, 2, 80}]; a] (* Michael De Vlieger, Dec 09 2020 *) PROG (PARI) lista(nn) = my(v=List([1]), x=1, y); print1(1); for(n=2, nn, if(!setsearch(Set(v), x=if(1==y=gcd(x, n), x+n+1, x/y)), print1(", ", x); listput(v, x))); \\ Jinyuan Wang, Dec 12 2020 (Python) from math import gcd from itertools import count, islice def A339571_gen(): # generator of terms a, aset = 1, {1} yield 1 for n in count(2): a = a+n+1 if (b:=gcd(a, n)) == 1 else a//b if a not in aset: aset.add(a) yield a A339571_list = list(islice(A339571_gen(), 30)) # Chai Wah Wu, Mar 18 2023 CROSSREFS Cf. A133058. Sequence in context: A088609 A163813 A109815 * A110653 A052309 A332905 Adjacent sequences: A339568 A339569 A339570 * A339572 A339573 A339574 KEYWORD nonn AUTHOR N. J. A. Sloane, Dec 09 2020 EXTENSIONS More terms from Jinyuan Wang, Dec 12 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 2 03:59 EST 2023. Contains 367505 sequences. (Running on oeis4.)